Possible Clues:

• Case of cryptic penned by syndic­ate of Guardian crossword setters arising
• Fido at last caught, dog collar is going on
• Going on
• It takes a firm start for the brute to be happening to press the bell
• The happening of a firm turn-up with a beastly round
• Round a couple of centuries, the old city is happening to get around
• How one might be happening to give a firm turn to a dog collar, perhaps